Brain Exercises: Get Your Mind in Shape

Sorry, sudoku. The best way to stay quick-witted might be to hit the gym

When it comes to self-improvement, I've always prioritized my brain over my body. Why waste an hour scurrying on a treadmill like a gerbil with a bunch of sweaty strangers when I could spend it curled up with a good book? Not being one to obsess about that real or imagined "last five pounds," I've never had the motivation it takes to become a regular at the gym. But I just learned something that might change my mind (in more ways than one): Exercise, far from being a boring time-suck, could actually make me smarter.

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Scientists have known for some time that exercise sparks growth of new brain cells in mice, particularly in the hippocampus, the area related to memory and learning. They recently also found that it boosts the production of a protein called brain-derived neurotrophic factor (BDNF), which stimulates the rate at which nerve cells bind to create new pathways, increasing the brain's storage capacity. Getting your body in motion gets your mind moving—both enhancing mental agility in the short term and protecting against cognitive decline in the long term. It might even benefit those with early Alzheimer's: In a study coauthored by University of Washington behavioral sciences researcher Laura Baker, PhD, in January's Archives of Neurology, older adults with mild cognitive impairment who engaged in regular aerobic training showed improved concentration and multitasking skills, while a control group that spent the same amount of time doing low-effort stretching exercises exhibited continued mental decline.

The best brain-boosting results come from heart-rate-raising exertion—specifically, running. In a study conducted by Charles Hillman, PhD, and published in the journal of the American College of Sports Medicine, when subjects were given memory tests both before and after 30-minute bouts of running on a treadmill, lifting weights, or sitting quietly, those who ran were significantly quicker and more accurate on the second round of tests, while the others demonstrated no change at all. "Other types of exercise, such as yoga, might have a stress-reducing meditative component," Baker says, "but it's aerobic exercise that seems to make the most difference to the brain."

There are a few theories as to why this might be: One is that dramatic changes in blood flow could bring more growth factors to the brain from other parts of the body, helping to limber up connection-forming neurons, whereas with an activity such as weight-lifting, those growth factors are likely to remain in the muscles. Another is that it improves energy metabolism, ensuring that the noggin receives sufficient glucose and fuel. And a third—my favorite—is that it literally clears out the gunk that makes us dullwitted. Evidently, our brains, similar to our hearts and teeth, can suffer from a buildup of bad stuff. "Low-density lipoprotein, a cholesterol, sticks to the blood-vessel walls and inhibits the exchange of nutrients and oxygen, so theoretically the brain is not getting what it needs," Baker says. "It's like if we let the plumbing in our house go too long without cleaning, we get a block of water to our faucets— that's basically what's happening in our brains as we age. Exercise can elevate high-density lipoprotein levels, which changes the lipid profile in the brain, while at the same time forcing blood through the pipes a little faster."

How often do we need to be hopping on the treadmill to whip our brains into the best possible shape? In general, what's good for the heart is good for the mind: A recent Duke University study found that middle-aged subjects who worked out only 30 minutes three to four times a week and ate a healthy diet showed a 30 percent improvement in mental function after four months. "Single bouts of exercise can temporarily increase cognitive function," Hillman says, "and data shows that getting regular exercise over time can increase both gray and white matter in the brain and make a big difference in how well you process and track information, stay on task, and allocate your mental resources." Who wouldn't want that? I always suspected gym devotees knew something I didn't. Turns out, they might know a lot more.